In American schools and media, pollution is often discussed in terms of what will happen in the future if we don't clean up our act now. But in China — where wildly overpopulated cities churn out toxic emissions, and hardworking plants produce 95 percent of the world's rare-earths elements — the effects of pollution accumulate like dust in an attic. Just last month, thousands of pig carcasses suddenly appeared in one of Shanghai's major water supplies. Farther west, runoff from local mining industries have turned clear rivers into milky waterways. In Beijing, the remnants of dangerously high pollution levels leave a thick smog that shrouds the city's skyscrapers. In response to public outcry over environmental degradation, China pledged last week to spend 100 billion yuan (about $6.1 billion) over the next three years to deal with pollution in one of its biggest and most troubled cities — Beijing. A photographic tour of the city's pollution problem:

Mounds of trash: Household garbage and construction waste are placed near a residential area in Beijing on March 22. (REUTERS/Jason Lee)

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Bubbling over: Bubbles spew up from domestic sewage in a polluted water channel, which flows to the Wenyuhe River, on the outskirts of Beijing on March 24. (REUTERS/Jason Lee)

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Burning waste: A resident throws a bag of household garbage into an open refuse room, where it will be burned, beside a road in a Beijing village, on March 24. (REUTERS/Jason Lee)

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Rinse and repeat: A woman washes clothes in a polluted canal in central Beijing on August 16, 2011. (REUTERS/David Gray)

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Covered: Aerial view of Beijing being enveloped in heavy smog on Feb 6. The heavy smog that affected north China early this year reportedly contained a heavy concentration of deadly organic compounds. The same chemicals were allegedly present in the deadliest fogs in history, including London's Great Smog of 1952, in which about 12,000 people died, and the photochemical smog in Los Angeles from 1940 to 1950, which killed about 800 people. (Imaginechina/Corbis)

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The day's catch: A woman wearing a chef's hat collects fish with a co-worker along the muddy shores of a polluted canal in central Beijing on October 21, 2010. The canal has been drained for cleaning, enabling fishermen and local residents to collect the small fish from the thick, black mud lining the bottom of the canal. Data from 2010 revealed almost a quarter of China's surface water to be so polluted that it is unfit even for industrial use, while less than half of total supplies are drinkable. (REUTERS/David Gray)

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Blind commute: Cars drive on Guomao Bridge on an overly hazy day in Beijing's central business district on Jan. 29. The city's air pollution returned to 'hazardous' levels earlier this year two weeks after record readings of small particles in the air sparked a public outcry. (REUTERS/Jason Lee)